Technical Field
This application relates to a fluid dispensing device, and, more particularly, to a fluid dispensing device for supplying select doses of fluid.
Background of Related Art
Devices for drawing and administering predetermined amounts or dosages of fluid are widely used in a variety of industries including, but not limited to, medicine. Dosage devices, such as hypodermic syringes, administer the drug directly in the bloodstream or in the tissue of the patient, who is thus directly affected by the drug. As a result, it is very important to assure that the precise dosage is administered at all times.
Commonly, hypodermic syringes include a graduated scale disposed on the body of the syringe. Utilizing the scale, an individual administering a drug will draw a quantity of the drug from a vial into the syringe, and then expel quantities of the drug until the precise dosage is achieved. This common measurement procedure can often be difficult and time-consuming, and more importantly, can be quite wasteful, as a quantity of the drug is often discarded in order to achieve the appropriate dosage. Other syringes are provided to hospitals or clinicians pre-filled. Still, the user relies on the scale or markings on the syringe to deliver the appropriate doses.
Quite often, medical professionals administering an injection may not have a clear view of the targeted body part of the patient. In this case, many rely on their experience to administer the desired dosage, which still may not be precise. Furthermore, those individuals who self-administer drugs may experience even more inconvenience that the professionals. Diminished hearing, eyesight and/or diminished dexterity of the user may lead individuals to draw or dispense an imprecise dosage of the drug into, or from the syringe. More significantly, it may lead them to draw or dispense an insufficient or excessive dosage into their body, which can result in life-threatening or worse, fatal, consequences.
Attempts have been made in the prior art to overcome these problems and provide some type of structure, which allows a person to accurately transfer the amount of medication to and from a syringe.
U.S. Pat. No. 4,252,159 to Maki teaches a dosage device including an elongated slat body on which a syringe is mounted by means of upstanding substantially Y-shaped brackets that are spaced from one another and extend upwardly from a flat exposed surface of the body. An adjustable top member threadedly engages an upstanding internally threaded element provided with externally located lands that, in turn, co-operate with an irregularly shaped knob so as to produce audible signals upon 360° revolution. The engagement and sound between the above-mentioned elements depends upon a number of factors which may include flexibility of the base or play between the threaded engagement such that the outwardly projected portion of the knob may pass over and in engagement with the lands.
U.S. Pat. No. 4,466,426 to Blackman discloses a syringe that has a plunger providing an audible sound upon a plunger being withdrawn from the barrel of a syringe.
U.S. Pat. No. 4,883,101 to Strong discloses a device for filling an injection syringe which incorporates a sound indicator provided with mechanical, electrical or an electronic sound device. A spring-loaded ball bearing is biased against a gear wheel and produces a distinctly audible clicking sound when the gear moves a single notch. A user counts the sounds accurately indicating the amount of liquid medicine drawn into the syringe when the attached syringe holder moves.
U.S. Pat. Nos. 5,741,232 and 5,795,333 to Reilly disclose a front loading syringe having a movable plunger rotatable on an injector housing. An audible indicating mechanism is activated when the syringe is essentially in the desired mounted position and includes ribs which function as volumetric gradations.
While the above noted patents are all directed to structures which attempt to overcome problems associated with dispensing proper dosage of medicine, these structures are rather complicated and inconvenient in use. The need therefore arises to have a simple structure of a dosing device that will allow a user to administer medicine in a simple and efficient manner.
Furthermore to minimize the aforementioned inconveniences, some of the known dosage devices have been provided with a tactile mechanism operative to generate a sound signal and/or increased resistance indicating displacement of the desired dosage of fluid into and from the dosage device.
U.S. Pat. Nos. 6,579,269 and 7,901,384 disclose syringes which attempt to provide a structure configured to reliably produce a distinct audible and tactile signal to the user indicating that the desired dosage of fluid has been drawn into, or displaced from, the dosage devices in a reliable, simple fashion. Although these patents disclose such signals to indicate dosage increments, their versatility is limited. This adds to the expense of the syringes and limits the manufacturer's ability to provide varied assortment of syringes tailored to applying predetermined or carefully controlled amounts of fluid.
It would be advantageous to provide syringes which facilitate adaptation to varied dosage needs in an efficient, reliable and cost effective way.